The present invention relates to slide projectors, and, in particular, to slide projectors utilizing gravity-feed during a projecting mode of operation.
U.S. Pat. No. 4,232,953, entitled "Gravity-Feed Rotary Slide Projector", describes a slide projector in which slides are transferred out of a rotary slide tray in which slides are stored in a radial orientation into registry with a projection aperture and back into the slide tray, solely by the force of gravity. The rotary slide tray is vertically arranged over a central hub portion of the slide projector that has a vertically arranged projection passage formed therein to guide movement of the slides past the projection apertures. Upon rotation of the rotary slide tray, slides radially drop from the tray under the influence of gravity into the projection passage until a sufficient number of slides accumulate in the passage to align one of the slides with the projection aperture. Sequential rotation of the tray results in passage of additional slides through the projection passage. In one embodiment, a specialized slide construction is used in which two individual slides are arranged in a carrier having like horizontal edges arranged adjacent. During a first cycle of the rotary slide tray, a first of the slides is projected, while during a second cycle the other of the slides is projected. Thus, two complete rotations of the rotary tray are required in order to project all of the slides. The patent indicates that a prismatic image inverter is required to selectively invert images when conventional single slides are projected.